As a coffee lover, and roaster at Famous Brands Coffee Company, I spend an inordinate amount of time seeking out the “best” coffee beans. I am taken by descriptions of exotic growing locations, the stories behind small batch coffee from individual farmers, and the process of finding the roast profile that best releases its natural flavours.

It’s a journey that the person who reaches for my coffee beans on the supermarket shelf, will never know, nor really appreciate. Yet, across the globe, there are thousands of us who simply carry on procuring, roasting and blending in anonymity, secure in the knowledge that those people will get to enjoy great coffee. Or so I thought.

The reality of what people really taste, was brought to the fore when on a business trip to another part of the country, I went to a coffee shop that is a customer and ordered an americano. I took one sip and thought to myself “they’ve used 5 year old coffee here!”

Marching up to the barista, feeling aggrieved both physically and mentally, I politely asked him if the coffee was still within its “best before” date because it tasted very flat. With surprise in his eyes, and the look of hurt spreading across his face, he replied that it was just a few weeks old, and I watched carefully as he proceeded to work his coffee machine to prepare another americano.

“Seems fine to me” he said, and while I couldn’t fault his preparation, I couldn’t have agreed less! What was going on here?

The answer came a few days later after visiting a number of different coffee shops and experiencing much the same result. So what was it?

It turns out that the water in the town was pumped from groundwater that was surrounded by limestone and was known to have a relatively high pH and alkalinity and to be “hard” water.

The high pH and alkalinity of the water had simply reduced the natural acidity in the coffee, and I guess only the residents of that town seemed not to notice it after years of getting used to it.

It made me realise that we underestimate the variability in the quality and taste of water and that this in turn has an impact on what we taste in our coffee.

After a little research, I had the Specialty Coffee Association of Europe (SCAE) Water Guide and could finally begin to understand the impact that water quality has on coffee. Yes, it’s a little technical but the gist is that the pH, alkalinity, general hardness and total dissolved solids, all have a role to play in defining the taste of coffee. As hardness and alkalinity increase above 100 and 60 parts per million respectively, the coffee tastes increasingly flat and chalky. Conversely, as these drop, there is an increasing acidity and sourness to the coffee.

The good news is that if you know what the composition of your water is, you can treat it and bring it in line with the guidelines that the SCAE recommend. This requires the addition of a specific type of water filtration system that will bring the water within the ideal range. Of course I knew about scale inhibiting water filters and the need for chlorine removal, but I hadn’t realised that there was more to worry about.  What is essential is that your filter system delivers water within the SCAE range. That is, if you want to avoid serving coffee that tastes like a lemon orchard or a pile of chalk dust.

Reading the SCAE Water Guide is a great way to understand jut how important water is to coffee, (although I kick myself for not realising that a beverage with 98.7% water must be influenced by it!) and even if the technical aspects are a little intimidating, the guide gives significant high-level context for any coffee roaster or barista.

On that note, discussing this with the barista I had so clearly offended, resulted in him fitting a filter system that reduced the hardness of the water. This not only limited limescale build up in the coffee machine, but when I tested his water quality (and I admit I was hoping to redeem myself), he was well within the SCAE water guidelines.

The proof was in the coffee!